https://openjdk.java.net/ 
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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package java.net;

import java.io.ObjectStreamException;


This class represents an Internet Protocol version 4 (IPv4) address.
Defined by 
RFC 790: Assigned Numbers,

RFC 1918: Address Allocation for Private Internets,
and RFC 2365:
Administratively Scoped IP Multicast

 Textual representation of IP addresses 

Textual representation of IPv4 address used as input to methods
takes one of the following forms:

    

  • d.d.d.d
    • 

  • d.d.d
    • 

  • d.d
    • 

  • d
    • 



 When four parts are specified, each is interpreted as a byte of
data and assigned, from left to right, to the four bytes of an IPv4
address.

 When a three part address is specified, the last part is
interpreted as a 16-bit quantity and placed in the right most two
bytes of the network address. This makes the three part address
format convenient for specifying Class B net- work addresses as
128.net.host.

 When a two part address is supplied, the last part is
interpreted as a 24-bit quantity and placed in the right most three
bytes of the network address. This makes the two part address
format convenient for specifying Class A network addresses as
net.host.

 When only one part is given, the value is stored directly in
the network address without any byte rearrangement.

 For methods that return a textual representation as output
value, the first form, i.e. a dotted-quad string, is used.

 The Scope of a Multicast Address 

Historically the IPv4 TTL field in the IP header has doubled as a
multicast scope field: a TTL of 0 means node-local, 1 means
link-local, up through 32 means site-local, up through 64 means
region-local, up through 128 means continent-local, and up through
255 are global. However, the administrative scoping is preferred.
Please refer to 
RFC 2365: Administratively Scoped IP Multicast

Since:1.4
/**
 * This class represents an Internet Protocol version 4 (IPv4) address.
 * Defined by <a href="http://www.ietf.org/rfc/rfc790.txt">
 * <i>RFC&nbsp;790: Assigned Numbers</i></a>,
 * <a href="http://www.ietf.org/rfc/rfc1918.txt">
 * <i>RFC&nbsp;1918: Address Allocation for Private Internets</i></a>,
 * and <a href="http://www.ietf.org/rfc/rfc2365.txt"><i>RFC&nbsp;2365:
 * Administratively Scoped IP Multicast</i></a>
 *
 * <h3> <a id="format">Textual representation of IP addresses</a> </h3>
 *
 * Textual representation of IPv4 address used as input to methods
 * takes one of the following forms:
 *
 * <blockquote><ul style="list-style-type:none">
 * <li>{@code d.d.d.d}</li>
 * <li>{@code d.d.d}</li>
 * <li>{@code d.d}</li>
 * <li>{@code d}</li>
 * </ul></blockquote>
 *
 * <p> When four parts are specified, each is interpreted as a byte of
 * data and assigned, from left to right, to the four bytes of an IPv4
 * address.

 * <p> When a three part address is specified, the last part is
 * interpreted as a 16-bit quantity and placed in the right most two
 * bytes of the network address. This makes the three part address
 * format convenient for specifying Class B net- work addresses as
 * 128.net.host.
 *
 * <p> When a two part address is supplied, the last part is
 * interpreted as a 24-bit quantity and placed in the right most three
 * bytes of the network address. This makes the two part address
 * format convenient for specifying Class A network addresses as
 * net.host.
 *
 * <p> When only one part is given, the value is stored directly in
 * the network address without any byte rearrangement.
 *
 * <p> For methods that return a textual representation as output
 * value, the first form, i.e. a dotted-quad string, is used.
 *
 * <h4> The Scope of a Multicast Address </h4>
 *
 * Historically the IPv4 TTL field in the IP header has doubled as a
 * multicast scope field: a TTL of 0 means node-local, 1 means
 * link-local, up through 32 means site-local, up through 64 means
 * region-local, up through 128 means continent-local, and up through
 * 255 are global. However, the administrative scoping is preferred.
 * Please refer to <a href="http://www.ietf.org/rfc/rfc2365.txt">
 * <i>RFC&nbsp;2365: Administratively Scoped IP Multicast</i></a>
 * @since 1.4
 */

public final
class Inet4Address extends InetAddress {
    static final int INADDRSZ = 4;

    
use serialVersionUID from InetAddress, but Inet4Address instance
 is always replaced by an InetAddress instance before being
 serialized 
/** use serialVersionUID from InetAddress, but Inet4Address instance
     *  is always replaced by an InetAddress instance before being
     *  serialized */
    private static final long serialVersionUID = 3286316764910316507L;

    /*
     * Perform initializations.
     */
    static {
        init();
    }

    Inet4Address() {
        super();
        holder().hostName = null;
        holder().address = 0;
        holder().family = IPv4;
    }

    Inet4Address(String hostName, byte addr[]) {
        holder().hostName = hostName;
        holder().family = IPv4;
        if (addr != null) {
            if (addr.length == INADDRSZ) {
                int address  = addr[3] & 0xFF;
                address |= ((addr[2] << 8) & 0xFF00);
                address |= ((addr[1] << 16) & 0xFF0000);
                address |= ((addr[0] << 24) & 0xFF000000);
                holder().address = address;
            }
        }
        holder().originalHostName = hostName;
    }
    Inet4Address(String hostName, int address) {
        holder().hostName = hostName;
        holder().family = IPv4;
        holder().address = address;
        holder().originalHostName = hostName;
    }

    
Replaces the object to be serialized with an InetAddress object.

Throws:
Returns:the alternate object to be serialized.
/**
     * Replaces the object to be serialized with an InetAddress object.
     *
     * @return the alternate object to be serialized.
     *
     * @throws ObjectStreamException if a new object replacing this
     * object could not be created
     */
    private Object writeReplace() throws ObjectStreamException {
        // will replace the to be serialized 'this' object
        InetAddress inet = new InetAddress();
        inet.holder().hostName = holder().getHostName();
        inet.holder().address = holder().getAddress();

        /**
         * Prior to 1.4 an InetAddress was created with a family
         * based on the platform AF_INET value (usually 2).
         * For compatibility reasons we must therefore write
         * the InetAddress with this family.
         */
        inet.holder().family = 2;

        return inet;
    }

    
Utility routine to check if the InetAddress is an
IP multicast address. IP multicast address is a Class D
address i.e first four bits of the address are 1110.

Returns:a boolean indicating if the InetAddress is an IP multicast address
/**
     * Utility routine to check if the InetAddress is an
     * IP multicast address. IP multicast address is a Class D
     * address i.e first four bits of the address are 1110.
     * @return a {@code boolean} indicating if the InetAddress is
     * an IP multicast address
     */
    public boolean isMulticastAddress() {
        return ((holder().getAddress() & 0xf0000000) == 0xe0000000);
    }

    
Utility routine to check if the InetAddress is a wildcard address.

Returns:a boolean indicating if the Inetaddress is a wildcard address.
/**
     * Utility routine to check if the InetAddress is a wildcard address.
     * @return a {@code boolean} indicating if the Inetaddress is
     *         a wildcard address.
     */
    public boolean isAnyLocalAddress() {
        return holder().getAddress() == 0;
    }

    
Utility routine to check if the InetAddress is a loopback address.

Returns:a boolean indicating if the InetAddress is a loopback address; or false otherwise.
/**
     * Utility routine to check if the InetAddress is a loopback address.
     *
     * @return a {@code boolean} indicating if the InetAddress is
     * a loopback address; or false otherwise.
     */
    public boolean isLoopbackAddress() {
        /* 127.x.x.x */
        byte[] byteAddr = getAddress();
        return byteAddr[0] == 127;
    }

    
Utility routine to check if the InetAddress is an link local address.

Returns:a boolean indicating if the InetAddress is a link local address; or false if address is not a link local unicast address.
/**
     * Utility routine to check if the InetAddress is an link local address.
     *
     * @return a {@code boolean} indicating if the InetAddress is
     * a link local address; or false if address is not a link local unicast address.
     */
    public boolean isLinkLocalAddress() {
        // link-local unicast in IPv4 (169.254.0.0/16)
        // defined in "Documenting Special Use IPv4 Address Blocks
        // that have been Registered with IANA" by Bill Manning
        // draft-manning-dsua-06.txt
        int address = holder().getAddress();
        return (((address >>> 24) & 0xFF) == 169)
            && (((address >>> 16) & 0xFF) == 254);
    }

    
Utility routine to check if the InetAddress is a site local address.

Returns:a boolean indicating if the InetAddress is a site local address; or false if address is not a site local unicast address.
/**
     * Utility routine to check if the InetAddress is a site local address.
     *
     * @return a {@code boolean} indicating if the InetAddress is
     * a site local address; or false if address is not a site local unicast address.
     */
    public boolean isSiteLocalAddress() {
        // refer to RFC 1918
        // 10/8 prefix
        // 172.16/12 prefix
        // 192.168/16 prefix
        int address = holder().getAddress();
        return (((address >>> 24) & 0xFF) == 10)
            || ((((address >>> 24) & 0xFF) == 172)
                && (((address >>> 16) & 0xF0) == 16))
            || ((((address >>> 24) & 0xFF) == 192)
                && (((address >>> 16) & 0xFF) == 168));
    }

    
Utility routine to check if the multicast address has global scope.

Returns:a boolean indicating if the address has is a multicast address of global scope, false if it is not of global scope or it is not a multicast address
/**
     * Utility routine to check if the multicast address has global scope.
     *
     * @return a {@code boolean} indicating if the address has
     *         is a multicast address of global scope, false if it is not
     *         of global scope or it is not a multicast address
     */
    public boolean isMCGlobal() {
        // 224.0.1.0 to 238.255.255.255
        byte[] byteAddr = getAddress();
        return ((byteAddr[0] & 0xff) >= 224 && (byteAddr[0] & 0xff) <= 238 ) &&
            !((byteAddr[0] & 0xff) == 224 && byteAddr[1] == 0 &&
              byteAddr[2] == 0);
    }

    
Utility routine to check if the multicast address has node scope.

Returns:a boolean indicating if the address has is a multicast address of node-local scope, false if it is not of node-local scope or it is not a multicast address
/**
     * Utility routine to check if the multicast address has node scope.
     *
     * @return a {@code boolean} indicating if the address has
     *         is a multicast address of node-local scope, false if it is not
     *         of node-local scope or it is not a multicast address
     */
    public boolean isMCNodeLocal() {
        // unless ttl == 0
        return false;
    }

    
Utility routine to check if the multicast address has link scope.

Returns:a boolean indicating if the address has is a multicast address of link-local scope, false if it is not of link-local scope or it is not a multicast address
/**
     * Utility routine to check if the multicast address has link scope.
     *
     * @return a {@code boolean} indicating if the address has
     *         is a multicast address of link-local scope, false if it is not
     *         of link-local scope or it is not a multicast address
     */
    public boolean isMCLinkLocal() {
        // 224.0.0/24 prefix and ttl == 1
        int address = holder().getAddress();
        return (((address >>> 24) & 0xFF) == 224)
            && (((address >>> 16) & 0xFF) == 0)
            && (((address >>> 8) & 0xFF) == 0);
    }

    
Utility routine to check if the multicast address has site scope.

Returns:a boolean indicating if the address has is a multicast address of site-local scope, false if it is not of site-local scope or it is not a multicast address
/**
     * Utility routine to check if the multicast address has site scope.
     *
     * @return a {@code boolean} indicating if the address has
     *         is a multicast address of site-local scope, false if it is not
     *         of site-local scope or it is not a multicast address
     */
    public boolean isMCSiteLocal() {
        // 239.255/16 prefix or ttl < 32
        int address = holder().getAddress();
        return (((address >>> 24) & 0xFF) == 239)
            && (((address >>> 16) & 0xFF) == 255);
    }

    
Utility routine to check if the multicast address has organization scope.

Returns:a boolean indicating if the address has is a multicast address of organization-local scope, false if it is not of organization-local scope or it is not a multicast address
/**
     * Utility routine to check if the multicast address has organization scope.
     *
     * @return a {@code boolean} indicating if the address has
     *         is a multicast address of organization-local scope,
     *         false if it is not of organization-local scope
     *         or it is not a multicast address
     */
    public boolean isMCOrgLocal() {
        // 239.192 - 239.195
        int address = holder().getAddress();
        return (((address >>> 24) & 0xFF) == 239)
            && (((address >>> 16) & 0xFF) >= 192)
            && (((address >>> 16) & 0xFF) <= 195);
    }

    
Returns the raw IP address of this InetAddress object. The result is in network byte order: the highest order byte of the address is in getAddress()[0]. 
Returns: the raw IP address of this object.
/**
     * Returns the raw IP address of this {@code InetAddress}
     * object. The result is in network byte order: the highest order
     * byte of the address is in {@code getAddress()[0]}.
     *
     * @return  the raw IP address of this object.
     */
    public byte[] getAddress() {
        int address = holder().getAddress();
        byte[] addr = new byte[INADDRSZ];

        addr[0] = (byte) ((address >>> 24) & 0xFF);
        addr[1] = (byte) ((address >>> 16) & 0xFF);
        addr[2] = (byte) ((address >>> 8) & 0xFF);
        addr[3] = (byte) (address & 0xFF);
        return addr;
    }

    
Returns the IP address string in textual presentation form.

Returns: the raw IP address in a string format.
/**
     * Returns the IP address string in textual presentation form.
     *
     * @return  the raw IP address in a string format.
     */
    public String getHostAddress() {
        return numericToTextFormat(getAddress());
    }

    
Returns a hashcode for this IP address.

Returns: a hash code value for this IP address.
/**
     * Returns a hashcode for this IP address.
     *
     * @return  a hash code value for this IP address.
     */
    public int hashCode() {
        return holder().getAddress();
    }

    
Compares this object against the specified object. The result is true if and only if the argument is not null and it represents the same IP address as this object. 
 Two instances of InetAddress represent the same IP address if the length of the byte arrays returned by getAddress is the same for both, and each of the array components is the same for the byte arrays. 
Params:
  • obj –   the object to compare against.
See Also:
Returns: true if the objects are the same; false otherwise.
/**
     * Compares this object against the specified object.
     * The result is {@code true} if and only if the argument is
     * not {@code null} and it represents the same IP address as
     * this object.
     * <p>
     * Two instances of {@code InetAddress} represent the same IP
     * address if the length of the byte arrays returned by
     * {@code getAddress} is the same for both, and each of the
     * array components is the same for the byte arrays.
     *
     * @param   obj   the object to compare against.
     * @return  {@code true} if the objects are the same;
     *          {@code false} otherwise.
     * @see     java.net.InetAddress#getAddress()
     */
    public boolean equals(Object obj) {
        return (obj != null) && (obj instanceof Inet4Address) &&
            (((InetAddress)obj).holder().getAddress() == holder().getAddress());
    }

    // Utilities

    
Converts IPv4 binary address into a string suitable for presentation.

Params:
  • src – a byte array representing an IPv4 numeric address
Returns:a String representing the IPv4 address in
        textual representation format
/**
     * Converts IPv4 binary address into a string suitable for presentation.
     *
     * @param src a byte array representing an IPv4 numeric address
     * @return a String representing the IPv4 address in
     *         textual representation format
     */
    static String numericToTextFormat(byte[] src)
    {
        return (src[0] & 0xff) + "." + (src[1] & 0xff) + "." + (src[2] & 0xff) + "." + (src[3] & 0xff);
    }

    
Perform class load-time initializations.

/**
     * Perform class load-time initializations.
     */
    private static native void init();
}